It is known that an aqueous emulsion of a liquid curable silicone composition, comprising (A) an organopolysiloxane having at least two silicon-bonded hydroxyl groups in one molecule, (B) an organohydrogenpolysiloxane having at least two silicon-bonded hydrogen atoms in one molecule, and (C) a curing catalyst, can be used as a precursor for the preparation of silicone rubber particles (see Japanese Patent Publication (Kokoku) (hereinafter referred to merely as “Kokoku”) Hei 4-17986). According to Kokoku Hei 4-17986, the aqueous emulsion is prepared by passing a silicone rubber composition consisting of components (A) through (C), with an addition of surface-active agent and water, through an emulsifier, such as a homomixer, homogenizer, colloid mill, etc., or by loading components (A) through (C) into a homogenizer, adding a surface-active agent, mixing the components, and then adding water and stirring the mixture. According to Practical Example 2 of the aforementioned publication, a mixture of a dimethylpolysiloxane having both molecular terminals capped with silicon-bonded hydroxyl groups with a methylhydrogenpolysiloxane having both molecular terminals capped with trimethylsiloxy groups is loaded into a storage tank. At the same time, a mixture of a dimethylpolysiloxane having both molecular terminals capped with silicon-bonded hydroxyl groups with dibutyltin dioctoate is loaded into another storage tank. After cooling, the mixtures are loaded into a static mixer where they are mixed together; the resulting mixture is fed to a colloid mill with simultaneous supply of water and a surface-active agent Mixing of all the components produces an aqueous emulsion.
However, when the inventors tried to carry out the aforementioned method, they could not easily form a uniform aqueous emulsion. This is because, even after cooling, component (C) caused a condensation reaction between components (A) and (B). This reaction led either to gellation or to partial curing prior to emulsification in water.